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From "Varun Saxena (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (YARN-5109) timestamps are stored unencoded causing parse errors
Date Thu, 19 May 2016 19:24:13 GMT

    [ https://issues.apache.org/jira/browse/YARN-5109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15291983#comment-15291983
] 

Varun Saxena commented on YARN-5109:
------------------------------------

Writing down what we discussed in the meeting with regards to this.

I have attached a WIP patch of whatever I had done so far.
Some things may have to be fine tuned(null checks etc.). Probably both limit and sizes need
not be passed into splitRanges. But anyways this works well for row keys as per my tests.

For column qualifiers,we could either do encoding of bytes(representing longs, ints, app ids')
before writing them into backend or use the same approach which we adopted for row keys i.e.
do not encode but split by ignoring separators for longs, ints, etc. till they are fully read.
I had a patch for former too but consensus seems to be towards latter.

Sangjin and Joep thought that we should reorganize our row key and column qualifier parsing
logic into a set of converters. It was decided that this approach will be explored further.

> timestamps are stored unencoded causing parse errors
> ----------------------------------------------------
>
>                 Key: YARN-5109
>                 URL: https://issues.apache.org/jira/browse/YARN-5109
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: timelineserver
>    Affects Versions: YARN-2928
>            Reporter: Sangjin Lee
>            Assignee: Varun Saxena
>            Priority: Blocker
>              Labels: yarn-2928-1st-milestone
>         Attachments: YARN-5109-YARN-2928.01.patch
>
>
> When we store timestamps (for example as part of the row key or part of the column name
for an event), the bytes are used as is without any encoding. If the byte value happens to
contain a separator character we use (e.g. "!" or "="), it causes a parse failure when we
read it.
> I came across this while looking into this error in the timeline reader:
> {noformat}
> 2016-05-17 21:28:38,643 WARN org.apache.hadoop.yarn.server.timelineservice.storage.common.TimelineStorageUtils:
incorrectly formatted column name: it will be discarded
> {noformat}
> I traced the data that was causing this, and the column name (for the event) was the
following:
> {noformat}
> i:e!YARN_RM_CONTAINER_CREATED=\x7F\xFF\xFE\xABDY=\x99=YARN_CONTAINER_ALLOCATED_HOST
> {noformat}
> Note that the column name is supposed to be of the format (event id)=(timestamp)=(event
info key). However, observe the timestamp portion:
> {noformat}
> \x7F\xFF\xFE\xABDY=\x99
> {noformat}
> The presence of the separator ("=") causes the parse error.



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